How to extend pack structure to other adults in the house?

So there are a couple of things to keep in mind to make this work.

The first is that the person who handles the dog the most is at the top of the pack structure. This is who I will refer to as "The Primary Handler". This person sets the rules for the dog and the other people within the house. So, for example, when someone else asks the dog to do something, and the dog doesn't listen, the primary handler should step in and ask for the same behavior. Once the dog performs the behavior, the second person should reset and do it again without the dog needing to check in again with the primary handler. The goal here is to teach the dog that any secondary handlers are backed by the primary handler.

The next thing to consider is that all three people need to be consistent in the rules and communication system established. So if you use marker training as your primary communication system, all three people need to use the system consistently and as all terms are defined. If all three people cannot maintain consistency, the dog will become confused and possibly frustrated. If only 2 of 3 people can maintain consistency, then the dog needs to be managed by only those 2 people and should have limited interaction with any remaining members of the household who cannot maintain the consistency set by the primary handler.

Pack structure is the expectations the dog has for each member of the pack. If the dog has learned it can push around any member of the house, and a clear and consistent boundary or rule isn't set by that member, the dog will not respect them.